Stud driver



B. A. MCKEAN STUD DRIVER Filed June 3, 1946 ffii I Patented Dec. 27, 1949 Boyd.. A. McKean, Erie, Pa.,1assig nor. to Titan 'Ilool Company,... Erie, Pa'., a'. corporation of'f Pennsylvania ZClaiins. l

In stud driversefon drivingstuds to a short projection.- height, it. has been necessary. to.: use. an.. open typeorI cylindrical stop for trippingthejaws at the end.- of-.the drive. Thishas, been necessary. to allow releasing; movement. of.Y the. jaws. TheA easier to `use closedtypeorcup shapedzstop having. a studreceiving guide opening. in ,the bottom'. has heretofore required tcofmuchfspace Since. the bot.- tcm wall of the stop;had.to be spacedffar enough. below` the vjaws to rpermitthe.jaw. releasing, move-v ment.- This invention. is. intended to. provide af retractable guide which/may be incorporated in. a. closed. type. stop', thus4 obtainingthe advantages of. the open .anctclosedftype stops.

inthe draw-ingsJig; 1 isa sectional elevation: ofa1. stud driver: im thei starting. position, Fig.. 2: is a2 similar. view. showing. the: jaws. closedfoni the stud.; Fig. 3 is-a. similarview showing. the, stud.. partially. driveni`fig. 4- is similar viewshowing they jaw drive released; Fig; ris-a-side-felevation.. partly'broken-awavof-the stop, and Figs..6 and 7` are similar views of modications..

In the drawings,V Il-indicatestheidriving.; member which. comprises; a, sleeveY having. a1. clutch 2: looselyheld irrits. upper. end by a ilange;y 3.011, a. threadedr retaining ring. if heldin 4place auloele ing ring 5.-. The. clutch. member 2; isthreaded.. to; receive. a. shank 6. fork attachment to. a.- driving.r motor... Sliclably received within. thesleeve. l-v is.- a'.v head 'l having, a tapered noncirci11arclutchjaw. i! receivable in asletdtin-the-clutch:member. 2. The axial; sliding.v of.. the-head1. is-.1imited by.' aset. screwiO-Which ts in.anf annular groove |.lf inthe head, The widthof. thegroove such. that the jaw. isf never completely-removed fromtlie slot. Qi. The head1 is;thereforefcontinuously' driven..

Slidably. received. withinthe` headl 1i are-f split." jairs. 4.2. having threaded stud gripping. jaws |32. 'lili-e jawsare retainedin:.the head by; set/.screwsthe inner ends of which are receivable'imanf nnlar. grooves.. l5.. inthe. jaws.: In. the lowermost position of. the jaws shown. in. Fig... l, thelowerf ends of. the jawsare split-bwacamsurfacc Iii-on. a step plugA Mihai/ing, asliank. i'slidably; received in .a pin. il held'. in. matinggroovesf 2 il in the j aws I3. Thestopplug. is urged. downward. by a;.coi1. spring 2l arranged between the pin, I9. and. the` plug il;

7ihen.thejaws are. in the stud grinpingposition; the plug lll is receivedlpwithin. an annular recess E2 in theijaws and the camsurface I6 is. slightly' above" a shoulder' atVA the lower endof.' thek recess 22'; In this position the jawsV are.`

cainn'ied together by a. cam; ring, 2'4" having a.

21 conical. cam suriacel. which. cooperates with.. a: conical surface 25;on.the jaws.. Thecamring is. journaled on-t-he.v1cwer end;V ofgrthe. head 1.-. by a.. ball-.thrustfbearing 7.1. andis held in. place. by, an

.l inwardly.. extending Aiange 28'. at the, lower. end

of, a. sleeve 24:1.r fixed. to, theA head.. In. the.- head.. are.. sockets 30. and 3J receiving retaining. balls. 3L and. clutchballsag.

During. the. usefof thefstud` setting. device the' ...head l iscontinuouslyJ driven. and the-balls, 32.

and'A ar-e urgedoutwardby centrifugal force.. Inthe. position shown in.-Fig. 1.the..reta.ining balls 32.? arereceived. in` an. annular groove 3.4. inthe sleeve. lv having. its. lower. edge defined. by. the.-

upper edgev of a cant ring.: pressed.v into the extending annular shoulder 4I; which. cooperates.

with; an. outwardly. extending. annular. shoulder 4Z; on. the sleeve-38 tdlimitthe.- downward move-y ment of.the,sleeve.39. The-lowerfendof the sleeve.- hasaplurality of. slots 43.which permitsud cient.. compression of.. the. sleeve 38.so that the shoulder .42'. can be. inserted.within the cup; 39..

Inthelowermost position of. the cup;3.9. the guide opening dil. is. slightly; hele-wthe lower.v ends of` the. jaws.. I2'. when; the jawsa-re. inthe open. or extended: position. showny in-F-ig. 1.. As the; studis.driven,.the lower end l01E-the .cup-shaped-mernber iicontactsrthe. Work and moves-.it upward until` it. strikes. the lower. end of. the. sleeve 38. At this. point. a.force.is.transmitted. tothe stud, moving the. jawsv ont` of. the head. 1. andl releasing thejawsfrom the. stud` The. lowermost. position. of. the. cupshapedfmember 3.9. may be just slightlyv below. the. drivingrpesitionof, the jaws illustrated, inv Figs..2. and 3.. This. permits the driving of studsin which. the desiredprojection. after. driving4 isiequal to the: length of. the stud` received:

betweenthefjaws in: the. drivingfposition. plus. the Y distance from the. lower. ends..of the-jaws to. the bottom of. the cunshapedmemben 3.9.. Since the` cunshapedmember.. 39;. is retractable due to the sliding, connectioniprovided. by. the shoulders 4I andata. theprcjectmnofthedriven stud can be'. substantiallylessthan hasbeenheretotore Dessible. with. stud,y driyers having.. closed. type.q stops with a stud guideopenng.r below thelower.. ends..

of the jaws. The closed type stop is easier to use since the guide facilitates the insertion of the stud. With the open type stop which would be approximated by the sleeve 38, the insertion of the stud is more difficult since the stud may strike on a corner of one of the jaws and throw the stud driver to one side.

In the modification shown in Fig. 6 the sleeve 38a has an inwardly extending annular shoulder 4Ia slidably receiving a cup shaped member 39a having in its bottom wall a ilared stud receiving guide opening 40a. After the sleeves 38a and 39a are assembled, a ring 44 is pressed on the upper end of the sleeve 39a forming an annular shoulder which limits the downward movement of the sleeve 39a. Upward movement of the sleeve 39a is limited by an outwardly projecting annular shoulder 45 which in the uppermost position engages the lower end of the sleeve 38a.

In the modification shown in Fig. '7 a sleeve 38D corresponding to the sleeves 38 and 38a has its lower end slidably received within a cup shaped member 39h having in its bottom wall a flared stud receiving guide opening 40D. At the upper end of the cup shaped member 39h is an inwardly extending ange Mb which cooperates with a ring 46 pressed on the lower end of the sleeve 38h to limit the downward movement of the cup shaped member 391?. The upward movement of the cup shaped member 39h islimited by engagement of the lower end of the sleeve 38h with the bottom wall of the cup shaped member.

The operation of both of these modications is the same as the previously described construction. In all of the stops there is a retractable guide which is below the jaws at the start of the stud driving operation to facilitate insertion of the stud and which is retracted to permit driving the stud to a shorter projection. All of the stops have the advantages of easy insertion of the stud obtainable with the closed type stop and the ability to drive studs to a short projected length obtainable with the open type stop.

At the start of the stud driving operation, the driver is positioned over a stud 41 which is received through one of the ared guide openings 40, 40a or 40h. As the stud driver is lowered, the upper end of the stud strikes the stop plug I'I and moves the plug upward into engagement with surfaces 48 on the jaws moving the jaws axially inward within the head l. During the initial inward movement the jaws are cammed together by cam surfaces 49 on the jaws which cooperate with the lower edge 50 of the cam ring 24. Upon further inward movement the jaws are cammed together by the tapered surface 25 on the cam ring. During this part of the inward movement of the jaws, the head 'I is retained in the position illustrated in Fig. 1 by the retaining balls 32 which are prevented from moving radially inward by surfaces 5I on the upper ends of the jaws. At the end of the initial inward movement of the jaws the groove I 5 in the jaws cornes opposite the retaining balls 32 and continued inward pressure is transmitted from the jaws through the surfaces 25 and 25 to the head, forcing the head inward within the sleeve I and causing the balls 32 to be cammed into the retaining groove I5 by engagement with the upper edge of the groove 34. At this point the parts of the driver are in the position illustrated in Fig. 2 in which the threaded ends I3 of the jaws are clamped on the upper end of the stud and are locked in the clamped position by the retaining balls 32 which are now positioned between the retaining groove I5 and the inner surface of the sleeve I above the groove 34. While the jaws are clamped on the stud, the jaws do not rotate since the cam ring 24 which cams the jaws 5 against the stud is journaled on the head.

As the lowering of the stud driver is continued, the head slides inward within the sleeve I to the position illustrated in Fig. 3 in which the clutch balls 33 are cammed out of the groove 36 by engagement with the lower edge of the cam ring 35 into inclined grooves 52 in the jaws I2.

'Ihe pitch of the grooves 52 is such that the normal driving position of the balls 33 is part way along the length of the grooves. The head I rotates relative to the jaws I2 until further inward movement of the jaws in the head is prevented by the pitch of the grooves 52. The inclined grooves cause the jaws to be driven inward by the driving torque providing the tight grip on the studs desirable for driving plated studs. This also compensates for wear of the threaded gripping surfaces I3 of the jaws.

At the start of the stud driving operation the guide openings 4), lila or 40h are spaced from the work slightly below the position illustrated in Fig. 2. As the stud driving operation continues, the driver moves downward as a unit to the position illustrated in Fig. 3 in which further downward movement of the sleeve I is prevented by engagement of the lower end of the sleeves 38, 33a or 35h with the stop surfaces on the cup shaped members 39, 39a or 39h. In this position the guide openings 5U, 45a or 45h are adjacent the lower ends of the jaws I2. From this point the head 'I and the jaws I2 move downward with the stud to the position illustrated in Fig. 4 in which the clutch balls 33 come opposite the groove 36 and are moved into the groove by centrifugal force, breaking the driving connection to the stud although the jaws are still clamped t0 the stud. The stud driver is released by an upward pull on the driver.

During the initial upward movement of the driver, the retaining balls 32 come opposite the groove 34 and are moved into the groove by centrifugal force, unlocking the jaws from the head l. Upon further upward movement of the driver the set screw I0 engages the upper edge of the groove II and stops the outward movement of the head. At this point the upward pull on the driver is eiective to break the cam surface 25 away from the jaws and permit the downward movement of the jaws by the spring 2I. The force of the spring 2l is transmitted to the jaws through the cam surfaces I6 causing the jaws to spread to the position illustrated in Fig. 1 in which the lower ends ocE the jaws are held in the spread position by surfaces 53 and 55 on the plug I'I and jaws I2 which prevent closing of the jaws until the plug I'I has been moved inward.

The retractable stop constructions have been disclosed as applied to the stud driver of my application Ser. No. 567,886, i'lled December 12,

1944. The retractable stops are obviously applicable to any form of stud driver in which the gripping and releasing of the stud is effected by inward and outward movement of the jaws.

What I claim as new is:

1. In a driver of the type having a head carrying jaws axially and radially movable therein, and cam means for closing the jaws on a stud upon axial movement of the jaws into the head, said jaws and head advancing with the stud as 75 it is driven, the combination of a work engaging guide moves inward a substantial distance as the head and jaws advance without exerting a force arresting the movement of the head.

2. In a drive of the type having a head carrying jaws axially and radially movable therein,

and cam means for closing the jaws on a stud i;

upon axial movement of the jaws into the head, said jaws and head advancing with the stud as it is driven, the combination of a work engaging stop for arresting the movement of the head and thereby causing outward movement of the jaws relative to the head at the end of the driving operation, said stop including a cup freely slideable axially and rotatable in the head with its bottom beneath the jaws and provided with a guide opening for the stud, a shoulder limiting 25 outward movement of the cup and the cup being normally held in its outermost position with the bottom of the cup below the jaws whereby the bottom of the cup engages the work toward the end of the stud driving operation and is moved inward relative to the head, and an abutment on the head engaged by the cup upon inward movement for arresting further movement of the head toward the work.

BOYD A. MCKEAN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,607,804 Snyder Nov. 23, 1926 1,807,265 Walker May 26, 1931 1,817,049 Weil Aug. 4, 1931 FOREIGN PATENTS Number Country Date 439,245 Germany Dec. 6, 1924 

